Reconfigurable Floor Plans May Boost Productivity

desired, consider perforated or slotted ceiling systems made from metal or wood. Most of these systems offer a variety of finishes and perforation patterns. To achieve an NRC rating of 0.90 or higher, a more open perforation pattern of 5% to 10% or more, and the use of a fibrous batt on the topside will most likely be required. If fiber erosion is a concern, some manufacturers offer encapsulated fibrous batts.

Should a ceiling not fit with a project’s desired aesthetic, know that an equal amount of absorption can be achieved with a variety of acoustic metal decks, spray-on deck treatments, suspended horizontally oriented clouds or islands, or vertically oriented baffles. The first step is to determine how many Sabins of absorption a ceiling with NRC 0.90 would have provided if it would have been used. For every 10 sq. ft. of open-office space, an NRC 0.90 ceiling would provide 9 Sabins of absorption. Another way to look at is to multiply the area of the open office by 0.9 Sabins/sq. ft. to determine the total number of Sabins required by any other solution.

Example: A 2,500-sq.-ft. open-office area should have 2,250 Sabins of absorption over it. (2,500 sq. ft. x NRC 0.90 = 2,250 Sabins)

The amount of sound absorption provided by acoustic products and materials varies by frequency. Therefore, the number of Sabins varies by frequency as well. Ideally, the acoustic solution used should provide the calculated total number of Sabins at all frequencies.

In reality, it becomes increasingly difficult to meet this ideal absorption goal for frequencies below 500 Hz. Try to reach this ideal goal at 500 Hz and above. It might be necessary to accept a lower amount of absorption below 500 Hz unless commercially available, specialty low-frequency absorbers are incorporated into the design. This is seldom done because the most common and distracting noises inside open offices areas occur at 500 Hz and higher.

Consider combining systems if no single approach provides all of the necessary absorption. For example, perhaps an array of vertically suspended acoustic baffles is desired visually, but too many baffles in too tight of an array are required. Instead, consider using an aesthetically pleasing baffle array and accomplish the additional absorption by using a lower-performing acoustic-metal deck above them or apply a treatment to the underside of the deck. Often, the best acoustic experiences are a result of using a variety of materials, each with their own acoustic advantages, arranged at different heights and orientations. There is no need to become overly concerned with heights and spacing. The most critical design aspect is the total amount of absorption. Try to distribute it somewhat uniformly over the entire open-office area.

Architects and specifiers should not feel limited by the acoustic requirements of the spaces they are designing. While it is has been known for decades that treatments of NRC 0.90 or higher are required over open

Should a ceiling not fi t with a project’s desired aesthetic, know that an equal amount of absorption can be achieved with a variety of other treatments and devices.

offices to achieve an acceptable level of speech privacy, there are numerous design options ranging in aesthetics and budget. With so many choices, the acoustics can, in fact, be the creative inspiration for the space. Also remember that an NRC 0.90 ceiling over an open office space is only one of at least five requirements needed to make a space successful. No single aspect alone guarantees acoustic success. CA Gary Madaras, PhD, ASA, INCE, Assoc. AIA, is the acoustics specialist at Rockfon North America, Chicago, where he helps designers and specifiers learn the Optimized Acoustics design approach. Madaras is a member of the Acoustical Society of America (ASA), the Canadian Acoustical Association (CAA), and the Institute of Noise Control Engineering (INCE). He can be reached at gary.madaras@rockfon.com.

PODCAST Learn about an acoustics ROI calculator designed for offi ce spaces in a new podcast editorial director Gary L. Parr recorded with Gary Madaras, author of this article, and Shirley Wodynski, executive director of the Ceilings & Interior Systems Construction Association (CISCA), Oak Brook, IL (cisca.org). Listen to the podcast at commercialarchitecturemagazine.com/1903facousticpod.

ADDITIONAL RESOURCES • “Acoustic Design Guide for Open Offi ces,” Warnock, A.C.C., National Research Council Canada report IRCRR-163, March 2004. • “Measurements of Sound Propagation between Mock-Up Workstations,” Bradely, J.S., Wang, C., National Research Council Canada report IRC-RR-145, January 2001. • “Acoustical Design of Conventional Open Plan Offi ces,” Bradley, J.S., National Research Council Canada report NRCC-46399, June, 2003. “A Renewed Look at Open Offi ce Acoustical Design,” Bradley, J.S. National Research Council Canada report NRCC-46399, August, 2003. “Acoustical Design for Open-Plan Offi ces,” Bradley, J.S., National Research Council Canada construction update no. 63, October, 2004.

Opening glass-wall systems allow a smaller footprint with more multifunctional, sound-controlled office enclosures and meeting rooms while reducing the need for extraneous dedicated rooms that serve only one function. Photos: NanaWall Systems

Reconfigurable Floor Plans May Boost Productivity Operable glass-wall systems could be an antidote to open-concept office complaints.

Matt Thomas, NanaWall Systems

The belief that open-concept floor plans increase collaboration and creativity has been recently challenged. A Harvard Business School, Cambridge, MA, study analyzed the effects of open floorplans on office spaces and concluded it’s not an ideal layout for optimal productivity. The study reported a 72% decrease in co-worker interaction along with an overall decline in productivity in offices that made the switch to an open-concept office. While emailing increased, with employees sending as much as 56% more email messages, face-to face communication between team members decreased from 5.8 hr. a week to 1.7 hr., while increased distractions and poor decision making were reported.

The emerging trend shifts away from an open concept and focuses on reconfigurable spaces that increase flexibility, natural light, and privacy through architectural elements such as glass-wall systems.

These contemporary workspaces ensure higher levels of productivity and satisfaction, increase a sense of flow and connectivity, and allow more-efficient space planning. The spaces are appealing to millennials who, according to a Forbes magazine study, today make up one out of every three Americans in the work force.

As architects and designers anticipate the evolution of office spaces, they should consider several factors that go into a productive office environment: flexibility, light, privacy, and sound. • Flexibility. Studies have shown that part of creating a productive work environment is providing a variety of workspaces that employees can choose at will. For example, large conference rooms can be divided into smaller, more intimate meeting rooms and offer collaborative or independent workspaces as needed. The next-generation